Long term evolution (“LTE”) of the Third Generation Partnership Project (“3GPP”), also referred to as 3GPP LTE, refers to research and development involving the 3GPP LTE Release 8 and beyond, which is the name generally used to describe an ongoing effort across the industry aimed at identifying technologies and capabilities that can improve systems such as the universal mobile telecommunication system (“UMTS”). The notation “LTE-A” is generally used in the industry to refer to further advancements in LTE. The goals of this broadly based project include improving communication efficiency, lowering costs, improving services, making use of new spectrum opportunities, and achieving better integration with other open standards. The 3GPP LTE project produces new standards as well as standards recommendations for the UMTS.
The evolved universal terrestrial radio access network (“E-UTRAN”) in 3GPP includes base stations providing user plane (including packet data convergence protocol/radio link control/medium access control/physical (“PDCP/RLC/MAC/PHY”) sublayers) and control plane (including radio resource control (“RRC”) sublayer) protocol terminations towards wireless communication devices such as cellular telephones. A wireless communication device or terminal is generally known as user equipment (also referred to as “UE”). A base station is an entity of a communication network often referred to as a Node B or an NB. Particularly in the E-UTRAN, an “evolved” base station is referred to as an eNodeB or an eNB. For details about the overall architecture of the E-UTRAN, see 3GPP Technical Specification (“TS”) 36.300 v8.7.0 (2008-12), which is incorporated herein by reference. For details of the radio resource control management, see 3GPP TS 25.331 v.9.1.0 (2009-12) and 3 GPP TS 36.331 v.9.1.0 (2009-12), which are incorporated herein by reference.
As wireless communication systems such as cellular telephone, satellite, and microwave communication systems become widely deployed and continue to attract a growing number of users, there is a pressing need to accommodate a large and variable number of communication devices transmitting a growing range of communication applications with fixed communication resources, and a growing need to conserve energy in base stations and wireless communication devices. A current topic in 3GPP of general interest is saving of energy in the cellular network. Integration of new network topologies into cellular networks has also attracted a high level of attention and interest both in industrial and academic circles. An example of a current study item in LTE/LTE-A related to heterogeneous cellular networks is deployment of macro, micro, pico, and femto base stations as well as relays in the same spectrum. A step in network integration is allowing local communication for devices (e.g., wireless communication devices or machines such as televisions and appliances) in the same communication system such as a cellular communication system when the devices are sufficiently close or are otherwise capable of using radio communication system resources in an efficient manner.
The processes to allow base stations to save power have been broadly discussed in 3GPP working groups. One technique is to scale the used effective bandwidth in a cell according to a load level. Another technique is to narrow the communication system bandwidth possibly turn off extra bands and carriers in LTE-A based communication systems or networks to obtain possible energy savings. One of the proposed techniques is to allow a base station to dynamically adjust its used communication system bandwidth in one carrier according to its load level. Dynamically adjusting used communication system bandwidth may be more attractive than saving power in the time domain due to the continuous need to transmit synchronization signals across the used communication system bandwidth.
Cellular and related communication systems can be described as employing primary and secondary communication system resources. Primary communication system resources (e.g., bandwidth) relate to used bandwidth in a primary communication system. For example, during light communication system utilization, a base station may utilize only a portion of its communication system bandwidth. The utilized portion of the communication system bandwidth would dynamically vary with communication system loading. Primary communication system resources are employed by a base station for a device (e.g., a wireless communication device) to communicate with another end device, with the base station acting as an intermediary node in the communication path.
Secondary communication system resources relate to the unused bandwidth in the primary communication system. The secondary communication system resources can be assigned by a base station to the secondary communication system to facilitate communications therein such as for device-to-device (“D2D”) or machine-to-machine (“M2M”) communication. Also, the secondary communication system may include, without limitation, a television, appliance (e.g., a refrigerator) or utility meter (for remote sensing/reading) configured to communication wirelessly with a user equipment or home base station.
The secondary communication system usage in future communication systems or networks is thus related to opportunistic usage of radio communication system resources and spectrum of the primary communication system or cognitive radio operation, wherein the primary communication system may be a LTE-A cellular network. A secondary communication system may utilize the spectrum of a primary communication system opportunistically if the secondary communication system does not degrade performance or otherwise interfere with the primary communication system.
For example, devices in the secondary communication system may be wireless communication devices that have an operator's subscriber identity module (“SIM”) card that provides authentication of such devices to the communication system or network. To allow local machine-to-machine or sensor communication, it may be feasible that these entities may use spectrum without a need for signaling towards the radio access network. Such operation in future cellular networks without an intermediary base station could save a substantial amount of energy and prevent extensive and otherwise unnecessary signaling load such as control and user plane signaling and scheduling between a base station and a number of devices (or machines). A present concern with device-to-device and machine-to-machine communication is how UTRAN/E-UTRAN can handle the number of future devices and machines compared to the number of normal cellular devices. Secondary usage is also referred to as future cognitive radios.
Integrating device-to-device or machine-to-machine communication into a cellular communication system introduces a number of challenges. One of the more problematic issues is how to perform communication system resource allocation among devices from the pool of primary communication system resources. In the case where the load in a cell due to cellular communication mode devices is lower than the current bandwidth allocation that would be provided for the carrier, the base station may decrease the used carrier bandwidth. Thus, there is a possibility to assign primary communication resources (e.g., frequency resources) outside the bandwidth used for the devices in the primary communication system that are still within the maximum allowed bandwidth of the primary communication system.
An unsolved problem is how a base station assigns and signals such secondary communication system resources that are not within the effective bandwidth, but within the maximum allowed bandwidth of the primary communication system. Another problem is how to use the same communication system resource allocation signaling in the cell when the ratio of used and unused bandwidth of the primary communication system changes. In view of the growing deployment of communication systems such as cellular communication systems, it would be beneficial for the purpose of enabling more efficient utilization of communication resources by the network to allocate secondary communication resources to facilitate communications in a secondary communication system that avoids the deficiencies of known communication systems for allocation of such resources.